Modulating the activity of vmPFC alters altruistic behavior: A tDCS study.

For centuries, scientists have pondered why people would help others at a cost to themselves even in the absence of expectation for future benefit. While a growing body of neuroimaging studies has suggested that the ventromedial prefrontal cortex (vmPFC) may be particularly critical for the regulation of altruistic behavior. However, evidence is still lacking in the field of neuroscience regarding the causal link between the region of vmPFC and pure altruistic behavior. In the present study, we designed a modified dictator game with a binary choice in the contexts of gain and loss that aimed to provide a simple and direct measure of participants' altruistic tendency. Using tDCS, we found that modulating the activity of vmPFC could significantly alter altruistic behaviors. Specifically, anodal stimulation of the vmPFC resulted in increasing altruistic choices compared with the cathodal stimulation, and the effect was found both in the gain and loss contexts. In addition, the subsequent inferences about others' altruistic behaviors were correlated with their own choices, and cathodal vmPFC stimulation resulted in a lower inference than sham stimulation in the gain context.